Combination compound tube



Aug. 4, 19'36. W. STEPHENS 2,050,213

COMBINATION COMPOUND TUBE Original Filed Aug. l2, 1931 Patented Aug. 4, 1936 UNITED .STATES PATENT OFFICE 2,050,213 coMmNnrroN coMroUNn TUBE William. Stephens, deceased, late o! Akron, Ohio, by Estelle Stephens, executrix, Akron, Ohio; said Stephens, assignor, by mesne assignments, to Wingfoot Corporation, Wilmington, Del., a corporation of Delaware Original application ugust 12, 1931, Serial o.

Divided and this application January 10, 1 933, Serial N0. 651,006

, v5 Claims. (Cl. 152f13) ice and long wear in the positions they assume in the tire and Wheel assembly.

Another object of the invention is to produce a rubber inner tube having an inner peripheral portion of a rubber compound which is of abrasive I resisting` nature, and an outer peripheral portion of a compound of high heat-resisting nature. In this manner the inner periphery of the tube can be of such compound that the tube can be used with drop center rims or with rims without tire 2O flaps, or under other .similar conditions. At the same time the outer peripheral portion of the tube can be of a compound which is particularly adapted to be positioned directly behind the tread portions of` the tire. The exact compositions of f the respective compounds can of course be widely varied 'to meet any requirements.

Anotherobject of the invention is to provide a composite body tube which is adapted tobe made by ordinary extrusion machinery. This object is accomplished by providing a plurality of cylinders l for the extrusion of rubber compounds, each cylinder being designed to extrude a particular type of stock and then passing the materials emerging from these cylinders through a common die which is designed to un/ite the various strips into a single composite tube or body.

The invention also contemplates the manufacture of fiat composite bodies and in this respectl it is particularly adapted to the making of a 40 combination tread and sidewall ,unit or member for use on pneumatic. tires. This is because the tread portion must be of a tough, long-wearing, comparatively expensive composition and the sidewalls may beof relatively cheaper materials or of a compound particularly designed to Withstand iiexure rather than wear. In this manner the tread and sidewalls can be made of any respective compositions and yet be produced and handled in a single unit or piecel of material. For a better understanding of the invention ref erence may now be had to the accompanying drawing forming a part of the specication ofv which:

Fig. 1 is a cross-sectional view partly in perspectiveot a portion of a vulcanized length of inner tube formed in accordance with the present invention;

. Fig. 2 is a cross-sectional view of the unvulcanized tube as it leaves the extruding apparatus; Fig. 3 is a cross-sectional view'of a tread and sidewall unit embodying the invention;

Fig. 4 is an elevational view of an extruding machine employed in practising the invention, and

Fig. 5 is an elevational view of a die head employed in the extrusion of the tread in the side- 10 Wall unit illustrated in Fig. 3.

The present application is a division of parent application Serial No. 556,578, iiled August 12, 1931, which has issued as Patent No. 1,952,470.

Referring to the drawing, the numeral IIl indi- .1 cates an inner tube formed in accordance with the method embodying the invention, which tube comprises an outer peripheral portion I2 of a rubber compound marked tread Wall stock and an inner peripheral portion I4 formed of a rubber 20 compound marked base wall stock. The walls I2 and I4 are preferably joined by butt joints I6 `which dene circumferentially extending lines.

The tread wall stock I2, that is the stock forming the portion of the tube adjacent the tread of 25 the tire, has high heat-resisting characteristics, While the base Wall stock forming the base or rim contacting portion of the tube has high abrasive resisting qualities. While the portions I2 and I4 have been particularly described as 30 possessing certain characteristics, it will be understood that the exact characteristics of the respective compounds may be Widely varied so that any desired qualities may be given to therespective K portions. f 35 In manufacturing composite tubes such as the tubes IIJ, a multi-cylinder extruding machine of the type illustrated in Fig. 4 may conveniently be employed.y This machine may comprise a pair of aligned cylinders I8 containing suitably driven 40 extruding means of the ordinary type, the cylinders I8 being connected with a common extruding head or die 2U. The twomaterials are formed into curved sheets by suitable die passages in the head 20 and are then passed through a common 45 circular opening Where the edges of the sheets are united to form a tube. Co-pending applications, Serial Numbers 50.1,332 and 509,388, which are assigned to the same assignee as the present application, illustrate apparatus of this type. 50

In constructing the tube I0, the material comprising the one portion of the tube will be fed to one of the extruding cylinders while the material comprising the other portion of the tube will be ders or machines will then feed the respective materials to the common extruding die 2li, through which they will be passed in the form of the un- 'vulcanized tube indicated in Fig. 2. Thereafter the unvulcanized tube is cut into proper lengths and provided with valve stems, the ends of each length are joined, and the tubes are vulcanized in unitary molds, as will be understood. The handling of the tube after the tubing operation is thus very similar to the handling of the ordinary inner tube built by the extrusion method.

While the method described and illustrated embodies forming a tube in which the portions I2 and I4 each comprise substantially equal halves of the tube I0, it will be seen that by changing the'form of theextruding head 20 that the portions I2 and I4 may be unequal, i. e., the one portion may extend a greater distance around the tube than the other. Moreover, it is not essential that the portions I2 and I4 be joined by butt joints I6, inasmuch as these joints may take the form of skived lap joints or the like.

Referring to the formo! the invention illustrated in Fig. 5, the numera1'22 indicates a tread and sidewall unit comprising a tread portion 26 and sidewall portions 26. 'I'he tread portion 26 is of tough. long-wearing, comparatively expensive rubber. 'I'he sidewall portions 26 may be of somewhat cheaper rubber particularly adapted to resist exing action.

In making the tread and sidewall unit 22, as illustrated in Fig. 5, the method followed is substantially the same as that described above in regard to making an inner tube, except that in this case the tuber head or die is preferably provided with a knife 28 which is placed as shown ln Fig. 5. so that as the material is extruded in the form oi' a tube, the knife 28 will cut the sidewall material along a longitudinal median line so that the tube may be then flattened into the shape shown in Fig. 5. A

It will be understood that the respective compositions of the sidewall and tread material may be widely varied to meet any desired operating conditions or to provide any quality of tire desired. Moreover, the respective thicknesses of the tread portion and sidewalls are dependent only upon the shape of the extruding head, which may be changed as desired. It will also be apparent that the tread portion 24 and the sidewall portions 26 may extend other than half way around the extruded tube, as explained above in regard to the inner tube, by merely changing the passages of the respective materials to the extruding die 20.

While the invention has been particularly described in regard to making inner tubes and tread and sidewall units, it will be evident that the principles thereof are broadly applicable not only to forming composite rubber bodies but also to forming composite bodies o f various other plastics.

It will also be understood that the invention contemplates not only forming the respective compounds of derent characteristics but also forming the compounds of diierent colors so that very attractive products result.

Although there is illustrated and described only the preferred embodiment of the invention, it will be apparent to those skilled in the art that the invention is not so limited but that various modications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

What is claimed is:

l. An inner tube comprising an inner peripheral wall of a compound of high abrasive resisting properties and an outer peripheral wail of a compound of high heat-resisting qualities, the walls being joined in butt joints.

2. An inner tube comprising an inner peripheral wall of a compound of high abrasive resisting properties and an outer peripheral wall of a' compound of high heat-resisting qualities, the walls being joined adjacent the sides of the inner tube.

3. An innertube comprising an inner periph-` eral wall of a compound of high abrasive resisting properties and an outer peripheral wall of a compound of high heat-resisting qualities.

4. A rubber inner tube adapted for use with "a pneumatic tire casing, said tube comprising a radially inner` wall of a single thickness adapted to contact with the tire-carrying rim and of a compound having high-abrasive-resisting properties, and a radially outer wall of a single thickness adapted to contact with the inner surface of the tread portion of the tire and of a compound of high heat-resisting properties, said inner and outer walls being joined together at the sides of the tube to form an air-tight container.

5. A rubber inner tube adapted for use witha pneumatic tire casing, said tube comprisinga radially inner wall of a single thickness adapted to contact with the tire-carrying rim and of -a. compound having high abrasive-resisting properties, and a radially outer wall of a single thickness adapted to contact with the inner surface of the tread portion of the tire, said inner and outer walls being joined together at the sides ot the tube to form an air-tight container.

, ESTELLE STEPHENS. Eecutria: of the Will of William Stephens, deceased. 

